Fluid pump



J- C. FISHER FLUID PUMP Aug. 9, 1960 2 Sheets-Sheet 1 Filed Oct. 24,1956 Fig. l

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I mm WH EB VF W.

C J N H O U I V. B

ATTORNEYS .guard against leakage.

ving 1,000 p.s.i.

,nited States This invention relates to an improved pump particularlysuitable for use in transmitting corrosive fluids, toxic or inflammablefluids, fluids containing abrasive materials in suspension, and otherfluids which cannot be satisfactorily handled by conventional pumps.

Displacement, rotary and centrifugal type pumps not only embody one ormore impellers and other moving .parts with which the liquid beingpumped comes in contact, but also a power-transmitting.element drivenfrom an external source. When such pumps are used to trans- 'mitcorrosive liquids, solvents, etc. the moving parts and other surfacescoming in contact with the liquid must either be made from a relativelycostly, corrosiveresistant material, or they must be provided with aprotective coating which after a relatively short period of use is aptto wear or become stripped, thus introducing contamination into theliquid being pumped. over, since such pumps are driven from an externalsource it is necessary to use packing glands or the like seals whichmust be periodically replaced in order to Consequently both the initialand maintenance costs of such pumps are relatively high.

The principal objects of the present invention are to provide a pumpwhich has completely sealed fluid carrying members so that no leakage ispossible, such as might occur with conventional centrifugal, vane,piston or rotary pumps; and to provide a simple, effective and reliablepump capable of handling molten materials under relatively highpressure, such for example as sodi tun at a temperature of 400 C. and apressure exceed- Other objects are to provide a pump capable of handlinga fluid containing solid or abrasive particles, such as encountered in acoolant system for machine tools, to provide a pump which can safelyhandle toxic materials such as radio-active substances and highlyinflammable or explosive fluids, etc., where leakage must be avoided,and to provide a pump the output of which may be varied without using avalve or the like.

Further objects will be apparent from a considera- 'tion of thefollowing description and the accompanying drawings, wherein:

Fig. 1 is an elevation, with parts broken away and shown in section, ofa simplified embodiment of my in- ;vention;

Fig. 2 is a section on the line 22 of Fig. 1; Fig. 3 is an axial sectionthrough one of the fluid barriers;

Fig. 4 is a schematic view of one of the fluid rectifiers; Fig. '5 is anelevation, with parts broken away and .shown in section, of another formof the invention emthe line 6 6 of Fig.

-- Fig. 7 is an elevation of the system as used from the Fig. 8 is asection on the line 88 of Fig. 5; and i Moretent Fig. 9 is alongitudinal section through one ofthe fluid rectifiers.

The principles underlying the present invention are substantially thesame as those set forth in my copending applications Serial Nos. 553,015and 578,777, filed December 14, 1955, and April 17, 1956, respectively,in that one or more elongate enclosure or tubes having radiallynon-expansible walls, i.e., walls which are nonexpansible in a directionperpendicular to the longitudinal axes and containing a propellant fluidis oscillated so as to produce an alternating fluid flow which acts on afluid in an associated circuit through the intermediary of a fluidrectifier so as to induce a unidirectional flow in theassociated'circuit. Where the propellant fluid and the fluid beingpumped should'not come in contact, a fluid barrier is interposed betweenthe enclosure and fluid rectifiers. Such a fluid barrier comprises apair of diaphragm operative to transmit pressure surges from one chamberto another, and one of these chambers is connected with the enclosureand the other is connected with the inlet of the fluid rectifier sothata unidirectional flow through the discharge port of the rectifier takesplace in response to an alternating flow in the enclosure and chamberconnected therewith.

The various parts of the system maybe made from any suitablecorrosion-resistant metal, or a chemically inert material such as apolyamide (nylon), polyethylene, a halogenated polyethylene (Teflon),polyvinylidene chloride (Saran), an acrylic acid resin or ester, asuitable polyester or an epoxy resin, provided they possess the desireddegree of rigidity, strength and fatigue resistance. In any case theparticular material selected will depend upon the type of fluid on orwith which the pump is to operate, the temperature of the fluid, etc.,and these same considerations are applicable to the ex ternal orassociated circuit and parts connected there- ,less steel tubing orother suitable material, as above pointed out, but where, as here shown,a single length of tubing is employed, its opposite ends are coiled toprovide the flexible sections 6 which permit the tube 5 to oscillateaxially.

The electrodynamic vibrator 4 comprises a fixed core 12 suitablyanchored to the base 1 and formed with a central opening 14 throughwhich the tube Spasses with adequate clearance and an annular recesswhich receives a field coil 15 which may be connected to any suitablesource of direct current so as to produce a high flux concentration inthe core 12. Integral with the core is a central projection 16 whichloosely fits about the tube 5 and firmly secured to the tube 5 in closeproximity to the outer end of the projection 16 is an armature 18 havingthree radial arms 20, each formed with an opening through which extendsa guide stud 21. The inner ends of these guide studs are threaded into aclosure plate 24, and the outer ends of the studs are suitably clampedto an upstanding bracket 25 secured to the base 1, the bracket 25 beingformed with an opening through which the tube 5 passes with adequateclearance.

'Ihe inner face of armature 18 is formed with a circular projection 2q6to which a sleeve 28is firmly secure d and an armature coil 30 is woundabout the sleeve 28 so :5 as to cause the armature and tube to oscillatein response to the passage of an alternating current therethrough. Acoil compression spring 32 acts against the closure plate 24 and theinner face of the armature 18, and a second spring 34 acts against theouter face of the armature 18 and the bracket 25. These springs 32 and34 not only normally hold the armature 18 in a central or neutralposition when the parts are at rest, but they are selected so that theirstiffness and characteristics produce a natural frequency of oscillationof the mass which is at least approximately the same as the frequency ofthe alternating armature coil current. Hence, the force produced by thearmature coil is used only to overcome the net resistance of the tube 5and associated parts, and the opposition of the propellant fluid to flowback and forth through the tube 5, coils 6 and fluid barrier 8.

Upper ends of .thecoils 6 are integral with inwardly directed extensions35 which are rigidly secured to the wall 2 by clamps 36. The coils 6thus provide flexible sections which support the opposite ends of thetube 5 so that the tube may be oscillated by the vibrator 4. The ends ofthe extensions 35 are connected with fluid barriers 8 each of whichcomprise a cylindrical outer chamber 38 within which is a bellows 40,the open end of which is connected to one of the extensions 35, throughan opening in one end of the chamber 38. The opposite end of the chamber38 is formed with an outlet opening 42 which is connected by a duct 44with the fluid rectifier 10.

Within the internal circuit or enclosure defined by the tube 5, coils 6,extensions 35 and bellows 40, is a propellant fluid such as mercury orthe like relatively heavy liquid, and within that part of the externalcircuit comprising the chamber 38 and ducts 44 is the fluid to bepumped. Oscillations imparted to the tube 5 by the vibrator 4 create analternating flow in the internal circuit which is transmitted throughthe bellows to the fluid in the chamber 38 and ducts 44, as indicated bythe arrows in Fig. 4.

The fluid rectifier 10, here shown schematically, may be of the sameconstruction as that shown in my aforementioned copending applications,but in any case is provided with inlet passages and 51 which areconnected with the ducts 44. These inlet passages are provided withbranches 52, 53, 54 and having check valves 56, 57, 58 and 59 or thelike means permitting fluid flow into the branches 52 and 54 and outthrough the branches 53 and 55, but opposing fluid flow in the oppositedirections. The branches 52 and 54 are interconnected by a duct and thebranches 53 and 55 are likewise interconnected by duct 62. An intakeline 64 is connected with the duct 60 and a discharge line 66 isconnected to the duct 62. Hence, an alternating fluid flow in the inletducts 44 creates a pulsating fluid flow inwardly through intake line 64and outwardly through discharge line 66, and during this process thecheck valves 56 and 59 are opened simultaneously while check valves 57and'58 are closed when the internal flow is from passage 50 to passage51, but when the internal flow is from passage 51 to passage 50 checkvalves 57 and 58 are opened and check valves 56 and 59 are closed.

In operation the internal circuit is completely filled with a propellantfluid such as mercury so as to be free from gas pockets and the fieldcoil 15 is connected with a suitable source of direct current. Thearmature coil 30 is connected through a control switch (not shown) witha source of alternating current so that upon closing the switch the tube5 is oscillated at the same frequency as that of the alternatingcurrent. By varying the frequency and/ or amplitude of the alternatingcurrent, the frequency of oscillation of the tube 5 and the accelerationimparted to the fluid therein may be varied. If, for example, a 60 cyclefrequency is used the tube 5 oscillates 60 times per second, and due tothe acceleration imparted to the fluid therein there will be 60 pressuresurges per 4 second acting on the fluid within each chamber 38 and as aresult there will be 120 pressure surges per second forcing liquid outthrough the discharge line 66 and the same number of surges drawingfluid in through the intake 64.

The alternating fluid flow in the internal circuit thus acts through thebellows 40 to create a unidirectional pulsating flow in the dischargeline 66 without either fluid coming in direct contact. Hence, it ispossible to pump fluids through the external circuit which wouldseriously react with the propellant fluid ofthe internal circuit. Ifdesired, the unidirectional pulsating flow in the external circuit maybe smoothed out by interposing between the intake and discharge lines 64and 66 a smoothing device such as disclosed in my copending applicationSerial No. 578,777, filed April 17, 1956.

The embodiment shown in Figs. 5 to 9 is, in principle, the same as thatof Figs. 1 to 4, but it is designed for three phase operation. Theparticular pump shown comprises an elongate base 71, such as a length ofchannel iron, having at opposite ends upstanding walls 72 and 74.Extending between the walls 72 and 74 are three parallel elongateenclosures or accelerator tubes 80, 81 and 82, preferably of stainlesssteel or the like material, having their axes lying in a common circleand spaced 120 apart. The opposite ends of the tubes are coiled toprovide flexible sections a, 80b, 81a, 81b and 82a, 82b. Three alignedelectrodynamic vibrators 84, 85 and 86, one for each tube, are mountedin spaced relation on the base 71 between the coiled ends of the tubes.The outer ends of the coils 80a, 81a and 82a are interconnected ashereinafter described and the outer ends of coils 80b, 81b and 82b areconnected with fluid barriers 90, 91 and 92 which in turn are connectedwith fluid rectifiers 94, 95 and 96 having interconnected intakes anddischarge ports hereinafter more fully described.

The electrodynar'nic vibrators are substantially identical, eachcomprising a back plate 100 and an annular outer pole piece or frontplate 101, both bolted to a spacer ring 102 having foot brackets 103bolted to the base 71. A conical-shaped permanent magnet 104, preferablyof high coercive force (Alnico), is secured to the back plate 100 andthe reduced end of this magnet carries an inner pole piece 106 spacedfrom the inner periphery of the outer pole piece so as to define anannular gap 108 which carries a radially directed, constant-densitymagnetic field. The back plates 100, magnets 104 and inner pole pieces106 are each provided with three aligned clearance openings throughwhichthe tubes 80, 81 and 82 extend, the openings in the back plates andinner pole pieces being appropriately hushed so as slidably to supportthe intermediate portions of the tubes.

A circular flanged plate 110, preferably of aluminum alloy, is securedto each of the accelerator tubes and each plate is formed with twoclearance openings through which the other accelerator tubes pass so asto permit them to be freely oscillated. One of these plates is normallydisposed midway between the adjacent inner pole piece of vibrator 84 andback plate of vibrator 85, the second between the pole piece of vibrator85 and back plate of vibrator 86 and the third plate is disposed midwaybetween the inner pole piece of vibrator 86 and the inwardly directedflange 111 of a cylindrical housing 112 (Fig. 5) which is bolted to theouter pole piece 101. Each flange plate carries a thin tube or sleeve114, preferably of stainless steel, which is concentric with the innerpole piece 106 and the free end portion of this tube projects into thegap 108. A sole noidal coil of wire is carried by the free end of thesleeve 114 and reacts with a substantially identical coil 116 woundabout the pole piece 106 in the opposite direction.

The coil 11-6 carries the same alternating current as the coil 115 andits purpose is to eounteractthe alternating magnetic field produced bythe coil 1 15. The coils 115 and 116 are connected in delta or Y in athree phase system, and any suitable means for ventilating the armatureand compensating coils may be provided, a conventional forced aircooling system (not shown) usually being adequate. I I

A pair of opposed helical coils 120 and 121, acting against each of theflanged plates 110, is provided and the inherent stiifness of thesecoils ;is designed for such avalue as to tune the moving mass oftheaccelerator tube (not including the propellant fluid inside it) tomechanical resonance at the frequency of the alternation of the armaturecurrents. This also helps to improve the power factor of the armaturewinding and greatly reduces the necessary force rating of the armaturecoil.

The corresponding ends of the coils 80a, 81a and 82a are interconnectedby fittings including a T 122, as shown in Fig. 6, and the coils 80b,81b and 821; are connected with the fluid barriers 90, 91 and 92,respectively, as shown in Fig. 7. Each of these barriers is identical tothe fluid value 8, shown in Fig. 3 and heretofore described, and theoutlet ducts 124, 125 and 126 of these barriers are connected to thefluid rectifiers 94, 95 and 96, respectively, each of which has the sameconstruction.

As shown in Fig. 9, each rectifier comprises a T 128 having itsintermediate branch 130 connected with an outlet duct of the associatedfluid barrier and its other branches are connected with tubes 131 and132 having Venturi passages 133 and 134 provided with ball checks 135,136 and retainer pins 137, 138. The corresponding ends of the tubes 131are connected with a header or collecting chamber 140 having an intake141, and the ends 132 are connected with a header 142 having a discharge144, the design being such that the ball checks opposed flow outwardlythrough the intake and inwardly through the discharge.

In operation the internal circuit, comprising the accelerator tubes 80,81 and 82, their associated coils and interconnected ducts, and theenclosures defined by the bellows within the fluid barriers, iscompletely filled with a propellant fluid such as mercury or otherliquid having a relatively high specific gravity. The external circuit,comprising the lines connected with the intake 141, discharge 144, thefluid rectifiers 94, 95 and 96 and parts connected therewith, containthe fluid to be pumped which may be any of the aforementionedsubstances, in-

I eluding molten sodium.

Where mercury is used as a propellant fluid with a three-phase sixtycycle alternating current, pressures of the order of 2,000 pounds persquare inch may be built up in the external circuit. As a practicalmatter the output of a pump constructed in the manner above-describedwill depend upon the operating frequency and size of the acceleratortubes. As a general rule, frequencies of the order of cycles per secondconstitute the lower practical limit and frequencies of the order of 100cycles per second constitute the upper limit. Low frequencies requirelarge tube displacements to obtain the required pressure and flow,Whereas at higher frequencies the necessary amplitudes are reduced.

While I have shown and described different desired embodiments of theinvention, it is to be understood that this disclosure is for thepurpose of illustration and various changes and modifications may bemade without departing from the spirit and scope of the invention as setforth in the appended claims.

I claim:

l. A fluid pump comprising an elongate tube having a radiallynon-expansible wall, the opposite ends of said tube terminating incoiled sections, a propellant fluid in said tube and coiled sections,manually controllable means for oscillating said tube at a uniformfrequency and in opposite directions along its longitudinal axis so asto produce an alternating fluid flow therein, and a fluid rectifierhaving an intake port, a discharge port, valve means for opposing fluidflow outwardly through said intake port and inwardly through saiddischarge sections and chambers connected therewith, means foroscillating said enclosure so as to produce an alternating fluid flowtherein, and a fluid rectifier having an intake port, a discharge port,and means connecting the intake and discharge ports to the otherchambers including means opposing fluid flow outwardly through saidintake port and inwardly through said discharge port so as to produce aunidirectional fluid flow through said discharge port in response toalternating fluid flow in said enclosure, flexible sections and chambersconnected therewith.

3. A fluid pump comprising an elongate tube having a radiallynon-expansible wall, means defining two pairs of chambers, a flexibleimpervious wall separating said chambers and operative to transmitpressure surges from one chamber to the other, flexible sections havingradially non-expansible walls connecting the end portions of said tubewith corresponding chambers, a propellant fluid in said tube, flexiblesections and chambers connected therewith, means for oscillating saidtube so as to produce an alternating fluid flow therein, and a fluidrectifier having an intake port, a discharge port, check valves opposingfluid flow outwardly through said intake port and inwardly through saiddischarge port, and inlets between said check valves connected with theother chambers so as to produce a unidirectional fluid flow through saiddischarge port in response to alternating fluid flow in said tube,flexible sections and chambers connected therewith.

4. A fluid pump comprising a plurality of elongate enclosures havingradially non-expansible walls, means defining a plurality of pairs ofchambers, a flexible impervious wall separating each pair of chambersand operative to transmit pressure surges from one chamber to the other,flexible sections having radially non-expansible walls connecting theend portions of said enclosures with corresponding chambers, apropellant fluid in said enclosures, flexible sections and chambersconnected therewith, means for oscillating said enclosures so as toproduce an alternating fluid flow therein, and a fluid rectifier havingan intake port, a discharge port, and means connecting the intake anddischarge ports to the other chambers including means opposing fluidflow outwardly through said intake port and inwardly through saiddischarge port so as to produce a unidirectional fluid flow through saiddischarge port in response/to an alternating fluid flow in saidenclosures, flexible sections and chambers connected therewith.

5. A fluid pump as set forth in claim 4, wherein there are threeenclosures which are oscillated simultaneously out of phase.

6. A fluid pump comprising a plurality of elongate tubes having radiallynon-expansible walls, means defining a plurality of pairs of chambers, aflexible impervious wall separating each pair of chambers and operativeto transmit pressure surges from one chamber to the other, flexiblesections having radially non-expansible walls connecting the endportions of said tubes with corresponding chambers, a propellant fluidin said tubes, flexible sections and chambers connected therewith, meansfor oscillating said tubes so as to produce an alternating fluid flowtherein, and a fluid rectifier having an intake port, a discharge port,check valves oppos ing fluid flow (islutwardly through said intake portand in- References Cited in the file of this patent Wardly throng saiddischarge port, and a plurality of inlets betweensaid check valvesConnected with the other UNITED STATES PATENTS chambers so as topr'csduce a unidirectional fluid flow 217,775 Collie July 22, 1879through said discharge port in response to all alternating 5 i V i 7fluid flow in said tubes, flexible sections and chambers FOREIGN PATENTSconneeted'therewith. 2

7. A fluid pum as set forth in claim 6, wherein there 5 Great Bntam of1835 are three tubes disposed in arallel relationshig whieh 5,138 GreatBritain of 1912 tubes are oscillated simultaneously 120 out of phase.

